Toshiba Lighting & Technology Corporation

Tatsuo Otabe

Seiji Ashida

Kiyoshi Saita

Hisashi Honda

Shigehisa Kawatsuru

Ariyoshi Ishizaki

Akira Itoh

Masuo Shibuya

Noriji Watanabe

Hisahi Honda

A high-pressure discharge lamp which includes a light-transmitting air-tight discharge container, an electrode formed of tungsten as a main component and fixedly sealed in the discharge container, and a discharge medium containing a halide of a light emitting metal and sealed in the discharge container. The surface of the electrode is defined as follows. That is, the average value of center line average roughness Ra of the surface, is set to 0.3 &mgr;m or less, or the average value of the center line average roughness Rz of the surface of the electrode, is set to 1.0 &mgr;m or less, or the average value of the surface area increasing rate of the surface of the electrode is set to 1.0% or less.

High-pressure discharge lamp

High-pressure discharge lamp including a limited amount of carbon remaining on an electrode surface

The present invention provides a high-voltage discharge lamp having an internal volume of 0.05 cc or less that is small yet maintains a desirable lifetime and a high luminous efficiency, a high-voltage discharge lamp device using the lamp, and a lighting apparatus using the lamp. The high-voltage discharge lamp comprises a ceramic discharge vessel that has a spherical, bulging section and a pair of small diameter cylindrical sections. The spherical, bulging section surrounds a discharge space. The small diameter cylindrical sections are connected to the ends of the spherical, bulging section. Electrode-integrated power-supplying conductors are used. Each conductor comprises a seal part and a halide-resistant part. The halide-resistant part having a proximal end connected to the distal end of the seal part. The distal end of the halide-resistant part projects into the spherical, bulging section of the translucent ceramic discharge vessel forming an electrode. A narrow gap is provided between the halide-resistant part and the inner surface of the small diameter cylindrical section. A discharge medium containing a metal halide and rare gas are filled in the translucent ceramic discharge vessel. When materials having a high average linear transmittance, such as YAG, are used as light-transmitting ceramics, the luminous efficiency of a small high-voltage discharge lamp will be increased.

High-voltage discharge lamp, high-voltage discharge lamp device, and lighting device

Growing community of inventors

Tokyo, Japan

Tatsuo Otabe